Seal sleeve for oil separator

ABSTRACT

In a hermetically sealed motor-compressor unit, a gas discharge tube extends into said unit to a position between the windings of the motor rotor. A circular rotor plate is mounted to the end of the rotor and has an opening formed therein through which the discharge tube is disposed. A flanged sleeve is positioned around the discharge tube and is held in place on the tube by spring tension of the sleeve itself. A flange portion of the sleeve seals a gap between the rotor plate and the discharge tube to prevent the flow of refrigerant gas and oil therethrough. The rotor plate is positioned so as to separate entrained oil from the refrigerant gas and is utilized for motor cooling.

United States Patent [1 1 Bellmer i 1 SEAL SLEEVE FOR OIL SEPARATOR [73]Assignee: Fedders Corporation, Edison, NJ.

[22] Filed: Apr. 24, 1972 [21] Appl. No.: 246,768

Primary Examiner-Carlton R. Croyle Assistant ExaminerRichard SherAttorney-David S. Kane et al.

[5 7 ABSTRACT In a hermetically sealed motor-compressor unit, a gasdischarge tube extends into said unit to a position between the windingsof the motor rotor. A circular rotor plate is mounted to the end of therotor and has an opening formed therein through which the discharge tubeis disposed. A flanged sleeve is positioned around the discharge tubeand is held in place on the tube by spring tension of the sleeve itself.A flange portion of the sleeve seals a gap between the rotor plate andthe discharge tube to prevent the flow of refrigerant gas and oiltherethrough. The rotor plate is positioned so as to separate entrainedoil from the refrigerant gas and is utilized for motor cooling.

8 Claims, 4 Drawing Figures PATENTEB UEC25 I973 1 SEAL SLEEVE FOR OILSEPARATOR BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates to hermetically sealed motor-compressor unitsin which high pressure discharge refrigerant gas from the compressor isutilized for motor cooling. The invention more particularly relates to adevice for separating entrained oil from the refrigerant gas.

2. Description of the Prior Art It has become common practice to utilizethe high pressure discharge gas from a compressor unit for cooling thecompressor motor in hermetically sealed motorcompressor units. In atypical hermetically sealed unit, the motor and compressor are mountedon a common shaft which is journaled in a bearing structure mountedwithin an outer casing. The bottom of the casing generally serves as areservoir for lubricating oil which is pumped under pressure to theinterface between the common shaft and the bearing. Thus, the atmospherein the casing contains a considerable amount of lubricating oil whichbecomes entrained in the refrigerant gas used for motor cooling. It isessential for proper operation of the compressor that the entrained oilbe separated from the gas prior to its discharge from the hermeticallysealed unit and that the oil be returned to the reservoir in the bottomof the casing.

Heretofore, various devices were developed for centrifugally separatingthe oil from the refrigerant gas. These devices were generallypositioned above the motor for intercepting the flow of oil ladenrefrigerant gas after the gas passed through the motor windings.

One example of such a device is shown in U.S. Pat. No. 3,176,914 issuedto D. C. Rinehart and entitled Hermetically Sealed Compressor Unit." Inthe Rinehart Patent, a circular disc is mounted to a rod which is fixedto the motor shaft. The disc rotates with the rotor and functions tointercept an upwardly flowing stream of discharge gas so that the oilentrained with the gas impinges on the rotating disc and is flungcentrifugally against the stator windings. The oil then runs in adownwardly direction through and along the stator windings to the oilreservoir in the lower portion of the casing. As the oil flows throughthe stator windings, it provides a degree of cooling to the windings inaddition to the cooling provided by the passage of discharge gas throughthe windings.

In the Rinehart Patent, a gas discharge tube is positioned above therotating disc for receiving the high pressure refrigerant gas from theunit and delivering it to the refrigeration system..The refrigerant gasmust flow around the rotating disc and through a narrow air gap betweenthe disc and the stator windings thereby impeding the gas flow to aconsiderable extent and reducing the efficiency of the compressor unit.As the gas passes through the narrow air gap, it develops an increasedvelocity and has a tendency to pick up oil that is deposited on thestator windings adjacent the air gap. Thus, some of the oil which wasseparated from the refrigerant is picked up by the high velocityrefrigerant gas thereby reducing the effectiveness of the oil separator.

SUMMARY OF TI-IE'INVENTION The present invention contemplates ahermetically sealed motor-compressor unit which utilizes compressordischarge gas for motor cooling and includes an oil separator. Themotor-compressor unit is divided into two chambers, one containing thecompressor and the other the motor. The compressor includes a dischargeport which is in communication with the motor chamber so that thedischarge gas passes into the motor chamber and flows through the statorand rotor windings of the motor to a discharge tube positioned at anopposite end of the motor chamber. The gas passing through the rotor andstator windings absorbs heat therefrom and thereby provides cooling forthe motor.

The motor and compressor are mounted on a common shaft which isjournaled in a bearing structure mounted within the casing of themotor-compressor unit. A lubricating system provides oil to theinterface between the shaft and bearing surfaces and this oil eventuallyescapes into the motor chamber where it is picked up and entrained inthe high pressure refrigerant discharge gas from the compressor. It isessential that the lubricating oil be separated from the refrigerant gasprior to the gas being circulated through the refrigeration system andreturned to the compressor intake. Slugging results when liquid oilenters the compressor intake and this greatly reduces compressor lifeand efficiency.

In order to overcome problems associated with the prior art devices, thepresent invention provides a circular rotor plate that is attached to anend of the rotor and has an opening formed in the center portionthereof. A discharge tube extends through the opening to a positionbelow the rotor plate and between the rotor windings. By positioning theend of the discharge tube below the rotor plate, the discharge gas flowis unimpeded and a pressure reduction does not result. Lubricating oilentrained in the gas impinges on the rotor plate and is flung in anoutwardly direction against the stator windings where the oil flows downthrough the stator windings to provide additional cooling for the motor.Since the discharge gas does not have to pass between the narrow gapbetween the rotor plate and the stator windings, the separated oil isnot remixed with the gas as in many of the prior art devices.

A flanged sleeve is placed around the discharge tube and is positionedto close a gap between the discharge tube and the rotor plate therebypreventing the flow of discharge gas through the gap. The flange alsoprevents oil from running down the stationary discharge tube to its openend where it would be sucked into the tube by the discharge gas.

The unique design of the flanged sleeve facilitates assembly of themotor-compressor unit and allows for the use of components havingreduced tolerances. Ideally, the gap between the discharge tube and therotor plate should be minimal; however, there was a tendency for therotating rotor plate to rub against the stationary discharge tubecausing the metal to chip. These chips would eventually cause failure ofthe compressor. The use of the flanged sleeve allows for a greater spacebetween the discharge tube and the rotor plate thereby preventingcontact between the rotor plate and discharge tube.

The primary objective of the present invention is to provide amotor-compressor unit having a more effective oil separator.

Another objective of the present invention is to provide an oilseparator for a motor-compressor unit that is less expensive and easierto assemble than those heretofore provided.

Another objective of the present invention is to provide an oilseparator for a motor-compressor unit that provides minimal restrictionof the discharge gas flow.

The foregoing objectives and advantages of the invention will appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawing, wherein oneembodiment of the invention is illustrated by way of example. It is tobe expressly understood, however, that the drawing is for illustrativepurposes only and is not to be considered as defining the limits of theinvention.

DESCRIPTION OF THE DRAWING FIG. 1 is a partial vertical section of amotorcompressor unit.

FIG. 2 is a vertical section of the flanged sleeve utilized in thecompressor of FIG. 1.

FIG. 3 is a plan view of the flanged sleeve of FIG. 2.

FIG. 4. is an elevation view of a flanged sleeve of FIG. 3.

DESCRIPTION OF THE INVENTION Referring to FIG. 1, there is shown aportion ofa motor-compressor unit having a hermetically sealed caseenclosing the motor-compressor. A bearing plate 12 is mounted withincase 10 and divides the case into a motor chamber 14 and a compressorchamber 16. A compressor 18 is mounted in compressor chamber 16 and amotor 20 is mounted in motor chamber 14.

Plate 12 has a bearing 22 through which is journaled a common shaft 24which extends into both the motor and compressor chambers. A roller, notshown, of compressor 18 and a rotor 26 of motor 20 are mounted to theshaft in their respective chambers. Motor 20 has a stator 28 mountedwithin case 10 concentric with rotor 26.

Shaft 24 has lubrication passages 30 formed therein to facilitatedelivery of lubricating oil to the interface between the shaft andbearing 22. Compressor 18 includes a pump 19 for delivering lubricatingoil under pressure to passages 30 from a reservoir of oil 21 containedin the bottom of case 10. Plate 12 has a port 32 formed therein so thatlubricating oil from the motor chamber may return to the compressorchamber to be deposited in the reservoir formed in the bottom of casing10.

For cooling purposes, compressor 18 has a discharge port 34 forproviding high pressure discharge refrigerant gas to motor chamber 14 sothat the gas flows through the motor chamber and around the rotor andstator to extract heat therefrom and thereby cool the motor. To thisend, the rotor is provided with longitudinally extending openingstherethrough as is commonly practiced in the art.

A counterweight 36 extending partially about the rotor is attached toone end of rotor 26 for balancing the rotor to prevent undesirablevibration. A rotor plate 38 is also connected to the end of rotor 26 bythe use of screws 40. Rotor plate 38 is circular and has a circularopening 42 formed in the center portion thereof. A gas discharge tube 44enters case 10 through a seal 46 and extends in a downwardly directionthrough opening 42 to a position below plate 38 and between the rotorwindings 48 of rotor 26. Gas discharge tube 44 has an open end 50positioned adjacent an end 52.0f shaft 24.

To prevent contact between discharge tube 44 and rotor plate 38, opening42 is made considerably larger than the outside diameter of dischargetube 44 so as to provide a space between the tube and plate of aboutone-eighth inch. Thus, the discharge tube and rotor plate may bemanufactured to less stringent tolerances at a reduced cost. Duringassembly the positioning of the rotor relative to the discharge tubebecomes less critical and thereby reduces assembly time and cost. Aflanged sleeve 54 is disposed about discharge tube 44 for closing thespace between the discharge tube and rotor plate.

Flanged sleeve 54 is shown in greater detail in FIGS. 2 through 4. Theinside diameter of a sleeve portion 55 is slightly larger than theoutside diameter of discharge tube 44 so that the sleeve may be easilyslid onto the tube. The sleeve portion has a U-shaped cutout 56 thatdefines a tab 58 which is bent in an inwardly direction to form a springfor retaining flanged sleeve 54 on the discharge tube by spring tension.The lower end of sleeve portion 55 terminates in an outwardly extendingflange 60 having an outer diameter greater than the opening 42 formed inrotor plate 38.

During assembly of motor-compressor unit, flanged sleeve 54 ispositioned so that the flanged portion 60 is in contact with rotor plate38. During the initial rotations of the rotor, the uneveness of therotor plate and vertical vibrations of the rotor cause the flangedsleeve to slide a slight distance away from the rotor plate. Thus, aminimum spacing between the flange 60 and the rotor plate is providedwithout contact being made on subsequent rotation.

In another embodiment, the rotor plate may be formed with three or moredimples on the top surface. Initially, the dismples contact the flangedportion, but the dimples wear away during the first few rotations andthe rubbing disappears providing a minimal space between the flange andthe rotor plate.

During operation of the motor-compressor unit, lubricating oil issupplied to the lubricating passages 30 so that the oil flows along theinterface of shaft 24 and bearing 22 and escapes into the motor chamber14 through the space 37 defined opposite the counterweight between therotor plate 38 and the top of the rotor windings 48. High pressuredischarge refrigerant gas from compressor 18 is provided to the motorchamher through port 34. The gas flows through and around the rotor andstator windings to extract heat therefrom and provide essential motorcooling. As the gas flows through the rotor and stator windings, thelubricating oil becomes entrained therein so as to flow in an upwardlydirection with the gas. As the gas flows through and between thewindings, it eventually impinges on the rotor plate where the oil isdeposited and is thereafter flung under centrifugal force into thestator windings 28. The oil then flows down through the windings untoplate 12 and through port 32 into compressor chamber 16 and reservoir21. As the oil passes through the stator windings, an additional amountof cooling is provided.

Since the open end 50 of the discharge tube is positioned adjacent end52 of shaft 24, the discharge gas does not flow directly into thedischarge tube but tends to impinge upon rotor plate 38 prior toentering the discharge tube. However, the gas does not have to flowthrough narrow gaps which greatly impede the flow as in the devices ofthe prior art. Flanged sleeve 54 provides a seal to prevent gas flowthrough opening 42 and also prevents oil from running down the sides ofthe stationary discharge tube where it may be sucked into the open end50 of the tube.

Thus, the present invention provides a more effective oil separator thatdoes not impede the flow of discharge gas and thereby reduce thecompressor efficiency. The invention allows for reduced component andassembly tolerances thereby greatly reducing the assembly time and costof a motor-compressor unit.

What is claimed is:

1. A motor-compressor unit comprising:

a sealed case;

a bearing plate,including a bearing, mounted in said case to divide thecase into a compressor chamber and a motor chamber;

a shaft journaled in said bearing and extending into both the motorchamber and compressor chamber;

compressor means mounted in said compressor chamber and drivablyattached to said shaft for providing compressed refrigerant gas to saidmotor chamber;

means for providing lubricating oil to the interface between the shaftand the bearing;

a motor having a rotor attached to said shaft and a stator mounted tosaid case in the motor chamber;

a rotor plate attached to the end of said rotor opposite the bearing,said rotor plate having an opening formed in the center thereof and saidrotor plate being spaced apart from said rotor end;

a gas discharge tube extending into said case and through the openingformed in the rotor plate; and

a flanged sleeve slidably mounted to said discharge tube for closing aspace between the discharge tube and the rotor plate, wherebylubricating oil entrained in the discharge gas impinges on the rotorplate and is flung under centrifugal force in an outwardly directiontowards said stator windings through the spacing between said rotorplate and rotor end.

2. A motor-compressor unit as described in claim 1, wherein thecompressor means includes a port communicating the compressor with themotor chamber.

3. A motor-compressor unit as described in claim 1, wherein thedischarge tube is in axial alignment with the shaft and has an open endpositioned adjacent an end of the shaft.

4. A motor-compressor unit as described in claim 1, wherein the rotorplate additionally includes counterweights disposed between the rotorplate and rotor for balancing the rotor.

5. A motor-compressor unit as described in claim 1, wherein the flangedsleeve comprises:

a sleeve portion formed and arranged to be slid over the discharge tube;and

a flanged portion formed at one end and extending in an outwardlydirection for closing the space between the discharge tube and the rotorplate.

6. A motor-compressor unit as described in claim 1, additionallycomprising spring means associated with the flanged sleeve formaintaining the flanged sleeve in position about the gas discharge tube.

7. A motor-compressor unit as described in claim 5, wherein the sleeveportion includes spring means for maintaining the sleeve in position onthe gas discharge tube.

8. A motor-compressor unit as described in claim 7, wherein the springmeans comprises an inwardly bent tab formed on the sleeve.

UNITED STATES PATENT OFFICE CERTIFICATE. OF CORRECTION pat No 3,781,138Dated December 25, 1973 Invntm-(S) Friedrich Otto Bellmer It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Inventor's name is misspelled. "Frederich" should be changedto--Friedrich--;

Col. 4, line 37, "dismples" should be--dimples-- and line 57, "into"should be--u nto- Signed and sealed this ll th day of May 19714..

(SEAL) At ts s t EDWARD M.FLETCHER, JR. C MARSHALL DANN AttestingOfficer Commissioner of Patents USCOMM-DC 60376-P69 rs GOVERNMENTPRINTING orHc: In" o-ass-su FORM Po-wso (1M9)

1. A motor-compressor unit comprising: a sealed case; a bearing plate,including a bearing, mounted in said case to divide the case into acompressor chamber and a motor chamber; a shaft journaled in saidbearing and extending into both the motor chamber and compressorchamber; compressor means mounted in said compressor chamber anddrivably attached to said shaft for providing compressed refrigerant gasto said motor chamber; means for providing lubricating oil to theinterface between the shaft and the bearing; a motor having a rotorattached to said shaft and a stator mounted to said case in the motorchamber; a rotor plate attached to the end of said rotor opposite thebearing, said rotor plate having an opening formed in the center thereofand said rotor plaTe being spaced apart from said rotor end; a gasdischarge tube extending into said case and through the opening formedin the rotor plate; and a flanged sleeve slidably mounted to saiddischarge tube for closing a space between the discharge tube and therotor plate, whereby lubricating oil entrained in the discharge gasimpinges on the rotor plate and is flung under centrifugal force in anoutwardly direction towards said stator windings through the spacingbetween said rotor plate and rotor end.
 2. A motor-compressor unit asdescribed in claim 1, wherein the compressor means includes a portcommunicating the compressor with the motor chamber.
 3. Amotor-compressor unit as described in claim 1, wherein the dischargetube is in axial alignment with the shaft and has an open end positionedadjacent an end of the shaft.
 4. A motor-compressor unit as described inclaim 1, wherein the rotor plate additionally includes counterweightsdisposed between the rotor plate and rotor for balancing the rotor.
 5. Amotor-compressor unit as described in claim 1, wherein the flangedsleeve comprises: a sleeve portion formed and arranged to be slid overthe discharge tube; and a flanged portion formed at one end andextending in an outwardly direction for closing the space between thedischarge tube and the rotor plate.
 6. A motor-compressor unit asdescribed in claim 1, additionally comprising spring means associatedwith the flanged sleeve for maintaining the flanged sleeve in positionabout the gas discharge tube.
 7. A motor-compressor unit as described inclaim 5, wherein the sleeve portion includes spring means formaintaining the sleeve in position on the gas discharge tube.
 8. Amotor-compressor unit as described in claim 7, wherein the spring meanscomprises an inwardly bent tab formed on the sleeve.